The effect of a high-frequency excitation on piping systems and supports is demonstrated. The influence of local plasticity on the dynamic behavior is shown in an analytical benchmark. The evaluation of several full-scale experiments resulted in rather large safety margins between calculated and allowed stresses. The stresses were calculated following the standard nuclear codes. No failure occurred in the tested structures even under extreme overloading. This demonstrates the high capacity of structures to survive dynamic load. A theoretical explanation is found in the effect of energy absorption by plastic deformation. This effect has been evaluated in a 1-DOF system showing for austenitic material 15 percent of material damping for 3 Sm. If this effect should be the result of modal response spectra analysis, the corresponding spectra would have to show very flat amplification ranges. The reduction of the overstresses by this approach could be shown in 2 numerical examples.

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